Coolant Temp Gauge

[MarksmanAkula]

Hey yall, just got a quick question. This past weekend I did some work to the cooling system of my Jeep. From what I could tell the system filled, and bled just fine.
Gauge would heat up, then stay a hair below half way, the way its always has.

BUT, is the coolant temp gauge a real gauge, or is it more of a dummy gauge? Like would it tell me if the jeep is overheating? I have no other way to tell if it would be overheating, as my scan tool doesn't read engine temps on this Jeep.

I've been suspicious of the lack of movement I've been able to catch from the radiator fan, even at operating temp per the gauge.

Overall just freaking myself out as i cant afford to brick this car at this point in time.

 

[GitEmSteveDave]

Dummy gauge.

I have a OBDII Bluetooth dongle & a cheap tablet that has GPS to run Torque in mine. Gives me a readout for coolant temp.

I made a gallery of the gauge position and actual temp it's running with my 03:

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[kejobe]

The gauge is NOT 100% accurate. It will move accordingly when operating properly though and is easily usable as a guide. If it goes above the 1/2 mark and keeps climbing, you are more than likely starting to overheat.

I have electric fans on mine and they don’t run as often as I would have expected them to when I bought it, but all is good.

With all this said, my opinion is your freaking yourself out as you said.

 

[MarksmanAkula]

Dummy gauge.

I have a OBDII Bluetooth dongle & a cheap tablet that has GPS to run Torque in mine. Gives me a readout for coolant temp.

I made a gallery of the gauge position and actual temp it's running with my 03:

xc_hide_links_from_guests_guests_error_hide_media

The pictures are helpful to visualize around what temp it may be at

 

[MarksmanAkula]

The gauge is NOT 100% accurate. It will move accordingly when operating properly though and is easily usable as a guide. If it goes above the 1/2 mark and keeps climbing, you are more than likely starting to overheat.

I have electric fans on mine and they don’t run as often as I would have expected them to when I bought it, but all is good.

With all this said, my opinion is your freaking yourself out as you said.

Thank you for the reply! I got a more recent update for my scan tool so I can finally read the Jeeps engine temp now.

Ill take it for a test drive tomorrow and monitor it more closely.

 

[tommudd]

All of my KJs run ( when fully warmed up ) at about 198 degrees give or take one or two degrees
and yes the temp gauge is an idiot gauge

 

[Michael Noland]

I've read that the CRD's show hotter than actual and need to be reprogramed. My Jeep dealer didn't know what I was talking about. Only time mine goes above center is when I'm towing something in the summer time.

 

[MarksmanAkula]

All of my KJs run ( when fully warmed up ) at about 198 degrees give or take one or two degrees
and yes the temp gauge is an idiot gauge

After hooking up the scan tool and watching the live data, at operating speeds the temp wouldn't get above 203-205. At idle it would get to 217 then drop back down to 205 when the fan kicked on.

So overall I think the radiator replacement was a success, and there is no air in the system.

Thank you to all who replied to this thread and helped me out!

 

[Jeremy-WI]

What do you mean by idiot gauge? Just that it doesn't set off alarms if it does go way over normal temp?

 

[tommudd]

What do you mean by idiot gauge? Just that it doesn't set off alarms if it does go way over normal temp?

Idiot gauge since it does not tell accurate temps, sitting exactly in the middle it can have a 50-60 degree difference above and not move off center

 

[Yetiboy01]

Idiot gauge since it does not tell accurate temps, sitting exactly in the middle it can have a 50-60 degree difference above and not move off center

Sounds like your gauge is stuffed, mine works fine tested against torque Pro app

 

[tommudd]

Sounds like your gauge is stuffed, mine works fine tested against torque Pro app

????? garage is stuffed has to do with temps how ?
And these that were tested over the last 17 years I have been playing with the KJs were other peoples, such as friends, customers etc,
that were having issues and I was checking them out to repair
I know what all of my KJs reads from the scan gauges right on top of their dashes ; )

 

[GitEmSteveDave]

What do you mean by idiot gauge? Just that it doesn't set off alarms if it does go way over normal temp?

On my Dodge 3500 Dualie, the temp is an actual gauge with actual temperature markings on it, 140f, 190f & 230f(in the red). I could tell when the thermostat first opened because the needle would swing down as the coolant from the tank rushed in, especially in winter.

I too use Torque Pro, and I posted a gallery above showing actual coolant temp vs. what the gauge shows using that app. From ~170f to 220f(the highest mine gets before the fan kicks in) the needle is touching the center black line and doesn't move.

 

[Jeremy-WI]

On my Dodge 3500 Dualie, the temp is an actual gauge with actual temperature markings on it, 140f, 190f & 230f(in the red). I could tell when the thermostat first opened because the needle would swing down as the coolant from the tank rushed in, especially in winter.

I too use Torque Pro, and I posted a gallery above showing actual coolant temp vs. what the gauge shows using that app. From ~170f to 220f(the highest mine gets before the fan kicks in) the needle is touching the center black line and doesn't move.

That likely means they save money on the gauges by not calibrating them to the resistance curve of the sensor itself as the thermistor doesn't work on a linear scale